Localization refers to the determination of a location of an object in three-dimensional space. Global Positioning System (GPS) technology is commonly used for localization in an outdoor environment. However, GPS is not as useful for indoor localization because signals from GPS satellites are generally not powerful enough to penetrate most buildings or other structures that create indoor environments.
A more useful tool for indoor localization involves wireless network. For example, wireless network fingerprinting creates a radio map of a given area based on received signal strength indication (RSSI) data from several access points and generates a probability distribution of RSSI values for a given latitude and longitude. Live RSSI values may then be compared to the fingerprint to find the closest match and generate a predicted location. Methods for predicting the location include Hidden Markov, Nearest Neighbor, and triangulation.